Process for preparing combinations of phenolphthalein with carbonates of alkali metal



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lPlEtUCESS FUR FREPARIHG OOMIBINATIEQNS F PHENQLPHTHALEIN V7 1TH CAREQNATES @F AlLIlLQlLZI METAL.

newness.

1W0 Drawing.

To all whom it may concern:

Be it known that I, Dr. ABA v. SZTANKAY, apothecary, a subject of the King oi Hungary, and a resident of the city of lDebreczen Kingdom of Hungary, have invented new and useful improvements in Processes for Preparing Combinations of Phenolphthalein with Carbonates of Alkali Metal, of which the following is a specification.

Usually the normal alkali metal salts of phenolphthalein are prepared by adding hydrate or carbonate of alkali metal (in the latter case it is of advantage to employ heat) to a solution of phenolphthalein the substances'reacting in the latter case according to the formula:

a". e. a diakali metallic salt of the phenolphthalein is formed, carbon dionid being liberated. l have found that no carbon diorid is termed it it employ concentrated aqueous solutions of carbonates of analkali metal for preparing the alkali salts of the phenolphthalein at the usual temperature, say at (1.. which proves that the above reaction does not take place under the circumstances stated.

l have tound that alkali metal combinations of the phenolphthalein are formed which have not been known hitherto and the exact constitution of which has not yet been ascertained. The analysis oi. the sodium compound agrees with the formula ec n o eu co Specification of Letters Patent.

Patented Nov. 2, lld tl.

Application filed June 159, will. t-Scrial No. 846.100.

pare said new combinations which possess qualities and properties altogether different irom those oi the diakali metallic salts of the phenolphthalein hitherto known. They are alkaline and exist only in aqueous solutions, being split into their component parts when the solvent evaporates at ordinary temperature. An aqueous solution for instance a 0.4% solution of the new combination is able to dissolve still a considerable proportion of pure phenolphthalein which is however fully separated again in the original quantity it the solution is allowed to stand. for 10 to hours. The specific grav1t of the solution remains therefore unaltere llvenif ll employ an excess of phenolphthalein there is no eii ervescence of carbon dioxid, no carbonate of alkali metal being formed. Un the contrary the purple aqueous solution-which retains this color even after the surplus oi? phenolphthalein has been removedis instantly decolored by the addition of: sodium bicarbonate and the phenolphthalein precipitated in white flakes. Acids act in the same manner, for instance f a surplus of carbon dioxid is conducted lnto the aqueous solution of the new combinations, phenolphthalein is precipitated according to the formula:

ac n o ,eua co eoo -en oz eo n o iauai-rco colored.

Ether, petrolether, Xylol, toluol C61 amyl-alcohol and chloroform CHljl do not extract the new combinations from their aqueous solutions when being shaken signifying that the combinations are insoluble in said solvents.

While phenolphthalein and its hitherto "Ill Ewample.

If a solution containing 0. 1% of the combination with carbonate of sodium is to be prepared 0.4 1'. fresh and pure phenolphthalein whic has suilered no deterioration and which has no odor is dissolved in 15 com. of absolute alcohol and this solution mixed at once with 800 com. of distilled water. The alcoholic solution of phenolphthalein forms a fine emulsion and to this a solution of 0.4 gr. carbonate of sodium (ab solutely free of water) in 135 com. of distilled water is added Without heating.

The phenolp'hthaleindissolves directly altogether and a pure purple liquid is formed containing the sesquisodiumcarbonate of phenolphthalein.

The combinations with the carbonates of aeeaaea other alkali metals are prepared in the same way.

The new combinations of carbonates of alkali metals with phenolphthalein may also be prepared by dissolving phenolphthalein in other solvents than water and treating this solution with an aqueous solution of alkali carbonate for instance by treating an alcoholic solution of phenolphthalein with an aqueous solution of carbonate of sodium.

I claim:

1. The process for preparing combinations of phenolphthalein with metal carbonates consisting in adding a solution of phenolphthalein to an aqueous solution of the metal carbonate at ordinary temperature, substantially as described.

2. The process for preparing combinations of phenolphthalein with carbonates of alkali metals consistin in adding an emulsion of phenolphthalein to an aqueous solutionof carbonate of alkali metal at ordi nary temperature, substantially as described.

DR. ABA v. SZTANKAY.

Witnesses HUGH KEMENY, ANDREW KELEMEK. 

